UWB channel measurements for short range radar applications

This paper presents channel measurements for short range radar applications in a frequency range from 5 GHz up to 7.5 GHz. For these measurements antennas with a half power beam width of 80° and circular polarization were provided by Maxim Integrated. The measured scenarios included a 28 mm copper pipe, a 26 cm × 28 cm aluminium plate, a bicycle and a 75 mm polokal plastic pipe. All measurements were conducted on flat concrete and grass. Through comparison with the radar equation and radar cross section calculations for the far field, it could be shown, that the size of the reflecting objects has to be used for the calculation of the near field (Fraunhofer Region) to far field transition. The measurements show that the radar cross section of an object declines the farther it comes into the near field.